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Old 04-11-2014, 09:47 AM   #10
Nomad Willy
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City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 16,150
Quote:
Originally Posted by psneeld View Post
Like many discussions there are extremes that people often refer to and make a big stink over....sure I have seen them too and agree that if you over or under prop and are in the few percent that blow up their engines prematurely surely should be used as examples.

But we have seen that people break the "rules" all the time with their engines...they idle them in the winter, they use more additives than an old persons home at pill time, they run'em hot, cold, use Walmart oil, change it every 50-200 hrs, etc...etc...

And they all claim long engine life and I have no reason to disbelieve them. I have seen the abuse an engine can take that makes many mechs scratch their heads.

A TFer here used to regularly post (and most believed his honesty) that Grand Banks overpropped ALL their engines for quite awhile...probably back before they got into the extremes....and possibly why they were grenading all those 475hp 3208 Cats.

So drawing between the line is usually the safest way to run your boat...but it's certainly NOT the only way.

AND like too many discussions here...where people want toenphasize "personal preferences" as absolutes.....

Some people MIGHT prefer lower RPM, quieter cruising, longer life on other components and ACCEPT 5000 vs 10,000 engine hours of total life or life before an overhaul...

But the best part is that if you do one or two of the "dangerous" things to your engine....for every "expert" that says you shouldn't do those things...there's no comprehensive "proof" to back up his/her claims...just experience that many times is limited in scope for the most part.

You make a lot of good points today psneeld. Good enough to merit re-posting.

It seems GB did overprop and Willard did too. And I'm sure others did also.

There's a lot of variation of opinion on how long an engine lasts at various engine loads. Marin used to say it was dependent on how many times the piston went up and down. In my own mind a 50% load and a 75% load seems excellent but there are so many variables.

psneeld wrote;
"there's no comprehensive "proof" to back up his/her claims". There is in my case (but only to a degree) in that I've always recommended or inferred that what the engineers and engine manufacturers recommend in their manuals should be taken seriously. However that is (to a significant extent) just another opinion. I've never heard of a study where engines were tested to destruction over a wide range of conditions so all we can do is pick the best opinion. And sometimes engine manufacturers recommend what is best relative to laws and the court or even convenience of the operator in addition to other variables that may include public opinion. There's that "opinion" word again.

So I think your point that there is no proof is true but not very usable information in that we all come to a conclusion on engine loading and frequently it's just a matter of what sounds good and feels good.

I still think the engine manufacturers and their engineers have the best information. The smallest amount of opinion and the greatest degree of objectivity. I wonder if GB and Willard owners in the 70s wondered why their engines wouldn't develop maximum power as installed in their boats. There must have been some interesting conversations. Or perhaps engine manufacturers did'nt recommend power loading in the 70s. They probably just left it up to boat manufacturers at that time.
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North Western Washington State USA
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